Image sensor device having a first lens and a second lens over the first lens

ABSTRACT

An image sensor device is provided. The image sensor device includes a substrate. The image sensor device includes a light-sensing region in the substrate. The image sensor device includes an isolation structure in the substrate. The isolation structure surrounds the light-sensing region. The image sensor device includes a grid layer over the substrate. The grid layer is over the isolation structure. The image sensor device includes a first lens over the light-sensing region and surrounded by the grid layer. The image sensor device includes a color filter layer over and in direct contact with the first lens. The first lens is embedded in the color filter layer. The image sensor device includes a second lens over the color filter layer.

PRIORITY CLAIM AND CROSS-REFERENCE

This application is a Continuation application of U.S. patentapplication Ser. No. 16/881,854, filed on May 22, 2020, which is aContinuation application of U.S. patent application Ser. No. 16/049,048,filed on Jul. 30, 2018, the entire of which is incorporated by referenceherein. The U.S. patent application Ser. No. 16/049,048 claims priorityto U.S. Provisional Application Serial Number 62/586,319, filed on Nov.15, 2017, which is herein incorporated by reference.

BACKGROUND

The semiconductor integrated circuit (IC) industry has experienced rapidgrowth. Technological advances in IC materials and design have producedgenerations of ICs where each generation has smaller and more complexcircuits than the previous generation. In the course of IC evolution,functional density (i.e., the number of interconnected devices per chiparea) has generally increased while geometric size (i.e., the smallestcomponent that can be created using a fabrication process) hasdecreased. Such advances have increased the complexity of processing andmanufacturing ICs. For these advances, similar developments in ICprocessing and manufacturing are needed.

Along with the advantages realized from reducing geometric size,improvements are being made directly to the IC devices. One such ICdevice is an image sensor device. An image sensor device includes apixel array (or grid) for detecting light and recording intensity(brightness) of the detected light. The pixel array responds to thelight by accumulating a charge. The higher the light intensity, thegreater the charge that is accumulated in the pixel array. Theaccumulated charge is then used (for example, by other circuitry) toprovide image information for use in a suitable application, such as adigital camera.

However, since the feature sizes continue to decrease, light collectionefficiency of image sensor devices continue to become more difficult toimprove. Therefore, it is a challenge to form image sensor devices withhigh light collection efficiency at smaller and smaller sizes.

BRIEF DESCRIPTION OF THE DRAWINGS

Aspects of the present disclosure are best understood from the followingdetailed description when read with the accompanying figures. It shouldbe noted that, in accordance with standard practice in the industry,various features are not drawn to scale. In fact, the dimensions of thevarious features may be arbitrarily increased or reduced for clarity ofdiscussion.

FIGS. 1A-1H are cross-sectional views of various stages of a process forforming an image sensor device, in accordance with some embodiments.

FIG. 1A-1 is a top view of the semiconductor substrate and the isolationstructure of FIG. 1A, in accordance with some embodiments.

FIG. 1C-1 is a top view of an intermediate structure of the image sensordevice of FIG. 1C, in accordance with some embodiments.

FIG. 1F-1 is a top view of an intermediate structure of the image sensordevice of FIG. 1F, in accordance with some embodiments.

FIG. 1G-1 is a top view of an intermediate structure of the image sensordevice of FIG. 1G, in accordance with some embodiments.

FIG. 1H-1 is a top view of an intermediate structure of the image sensordevice of FIG. 1H, in accordance with some embodiments.

FIG. 2 is a top view of a variation of the intermediate structure of theimage sensor device of FIG. 1G-1, in accordance with some embodiments.

FIG. 3 is a top view of a variation of the intermediate structure of theimage sensor device of FIG. 1G-1, in accordance with some embodiments.

FIG. 4A is a top view of a variation of the intermediate structure ofthe image sensor device of FIG. 1G-1, in accordance with someembodiments.

FIG. 4B is a perspective view of the lenses of FIG. 4A, in accordancewith some embodiments.

FIGS. 5A-5B are cross-sectional views of various stages of a process forforming an image sensor device, in accordance with some embodiments.

FIG. 6 is a cross-sectional view of an image sensor device, inaccordance with some embodiments.

FIG. 7 is a cross-sectional view of an image sensor device, inaccordance with some embodiments.

FIG. 8 is a cross-sectional view of an image sensor device, inaccordance with some embodiments.

FIG. 9 is a cross-sectional view of an image sensor device, inaccordance with some embodiments.

FIG. 10 is a cross-sectional view of an image sensor device, inaccordance with some embodiments.

DETAILED DESCRIPTION

The following disclosure provides many different embodiments, orexamples, for implementing different features of the subject matterprovided. Specific examples of components and arrangements are describedbelow to simplify the present disclosure. These are, of course, merelyexamples and are not intended to be limiting. For example, the formationof a first feature over or on a second feature in the description thatfollows may include embodiments in which the first and second featuresare formed in direct contact, and may also include embodiments in whichadditional features may be formed between the first and second features,such that the first and second features may not be in direct contact. Inaddition, the present disclosure may repeat reference numerals and/orletters in the various examples. This repetition is for the purpose ofsimplicity and clarity and does not in itself dictate a relationshipbetween the various embodiments and/or configurations discussed.

Furthermore, spatially relative terms, such as “beneath,” “below,”“lower,” “above,” “upper” and the like, may be used herein for ease ofdescription to describe one element or feature's relationship to anotherelement(s) or feature(s) as illustrated in the figures. The spatiallyrelative terms are intended to encompass different orientations of thedevice in use or operation in addition to the orientation depicted inthe figures. The apparatus may be otherwise oriented (rotated 90 degreesor at other orientations) and the spatially relative descriptors usedherein may likewise be interpreted accordingly. It should be understoodthat additional operations can be provided before, during, and after themethod, and some of the operations described can be replaced oreliminated for other embodiments of the method.

FIGS. 1A-1H are cross-sectional views of various stages of a process forforming an image sensor device 100, in accordance with some embodiments.As shown in FIG. 1A, a semiconductor substrate 110 is provided, inaccordance with some embodiments. The semiconductor substrate 110 has afront surface 112 and a back surface 114 opposite to the front surface112, in accordance with some embodiments.

The semiconductor substrate 110 may be a silicon substrate doped with aP-type dopant such as boron, in which case the semiconductor substrate110 is a P-type substrate. Alternatively, the semiconductor substrate110 could be doped with another suitable dopant. For example, thesemiconductor substrate 110 may be a silicon substrate doped with anN-type dopant such as phosphorous or arsenic, in which case thesemiconductor substrate 110 is an N-type substrate. The semiconductorsubstrate 110 may include elementary semiconductor materials such asgermanium.

As shown in FIG. 1A, a portion of the semiconductor substrate 110 isremoved to form a trench 116 in the semiconductor substrate 110, inaccordance with some embodiments. The trench 116 extends from the frontsurface 112 into the semiconductor substrate 110, in accordance withsome embodiments. The trench 116 surrounds portions of the semiconductorsubstrate 110, in accordance with some embodiments.

As shown in FIG. 1A, a liner layer 122 is formed in the trench 116, inaccordance with some embodiments. The liner layer 122 includes oxide(such as silicon oxide), in accordance with some embodiments. The linerlayer 122 is formed by a thermal oxidation process, in accordance withsome embodiments.

As shown in FIG. 1A, an insulating layer 124 is formed over the linerlayer 122, in accordance with some embodiments. The insulating layer 124is filled in the trench 116, in accordance with some embodiments. Theinsulating layer 124 is made of silicon dioxide, silicon nitride,silicon oxynitride, fluoride-doped silicate glass (FSG), a low-Kdielectric material, another suitable insulating material, orcombinations thereof. The insulating layer 124 is formed using adeposition process, such as a chemical vapor deposition process, aphysical vapor deposition process, or another suitable depositionprocess.

The insulating layer 124 and the liner layer 122 together form anisolation structure 120, in accordance with some embodiments. In someembodiments, the isolation structure 120 is used to define subsequentlyformed light-sensing regions in the semiconductor substrate 110, and toelectrically isolate neighboring devices (e.g. transistors) from oneanother.

FIG. 1A-1 is a top view of the semiconductor substrate 110 and theisolation structure 120 of FIG. 1A, in accordance with some embodiments.As shown in FIGS. 1A and 1A-1, light-sensing regions 118 are formed inthe portions of the semiconductor substrate 110 surrounded by theisolation structure 120, in accordance with some embodiments. Thelight-sensing regions 118 are also referred to as radiation-sensingregions, in accordance with some embodiments.

The light-sensing regions 118 are formed using one or more ionimplantation processes or diffusion processes, in accordance with someembodiments. The light-sensing regions 118 are doped with a dopingpolarity opposite from that of the semiconductor substrate 110, inaccordance with some embodiments. The light-sensing regions 118 extendfrom the front surface 112 into the semiconductor substrate 110, inaccordance with some embodiments.

The light-sensing regions 118 are operable to sense incident light (orincident radiation) that enters the light-sensing regions 118. Theincident light may be visible light. Alternatively, the incident lightmay be infrared (IR), ultraviolet (UV), X-ray, microwave, other suitabletypes of light, or a combination thereof.

Image sensing elements are formed over the light-sensing regions 118,and for the sake of simplicity, detailed structures of the image sensingelements are not shown in figures of the present disclosure, inaccordance with some embodiments. The image sensing elements includepinned layers, photodiode gates, reset transistors, source followertransistors, and transfer transistors, in accordance with someembodiments.

The transfer transistors are electrically connected with thelight-sensing regions 118 to collect (or pick up) electrons generated byincident light (or incident radiation) traveling into the light-sensingregions 118 and to convert the electrons into voltage signals, inaccordance with some embodiments.

As shown in FIG. 1A, an interconnection structure 130 is formed over thefront surface 112, in accordance with some embodiments. Theinterconnection structure 130 includes a number of patterned dielectriclayers and conductive layers that couple to various doped features,circuitry, photodiode gates, reset transistors, source followertransistors, and transfer transistors. For example, the interconnectionstructure 130 includes an interlayer dielectric (ILD) layer 132 and amultilayer interconnection (MLI) structure 134 in the ILD layer 132.

The MLI structure 134 includes conductive lines 134 a and vias (orcontacts) 134 b connected between the conductive lines 134 a or betweenthe conductive lines 134 a and the image sensing elements (not shown).It should be understood that the conductive lines 134 a and the vias 134b are merely exemplary. The actual positioning and configuration of theconductive lines 134 a and the vias 134 b may vary depending on designneeds and manufacturing concerns.

Afterwards, a carrier substrate 140 is bonded with the interconnectionstructure 130, in accordance with some embodiments. The carriersubstrate 140 includes a silicon substrate, a glass substrate or anothersuitable substrate. Thereafter, as shown in FIGS. 1A and 1B, a thinningprocess is performed to thin the semiconductor substrate 110 from theback surface 114. The thinning process may include a chemical mechanicalpolishing process.

Afterwards, as shown in FIG. 1B, the semiconductor substrate 110 isflipped over, and a trench 119 is formed in the semiconductor substrate110, in accordance with some embodiments. The trench 119 extends fromthe back surface 114 into the semiconductor substrate 110, in accordancewith some embodiments. The trench 119 is between each two adjacentlight-sensing regions 118, in accordance with some embodiments. Thetrench 119 surrounds each of the light-sensing regions 118, inaccordance with some embodiments.

In some embodiments, the trench 119 is above the isolation structure120. In some embodiments, the trench 119 exposes the isolation structure120. The isolation structure 120 has a surface (or an end surface) 120 afacing the back surface 114, in accordance with some embodiments. Thetrench 119 exposes the surface 120 a, in accordance with someembodiments. The trench 119 exposes the liner layer 122, in accordancewith some embodiments.

Afterwards, as shown in FIG. 1C, an insulating layer 150 is formed inthe trench 119, in accordance with some embodiments. The insulatinglayer 150 is also referred to as a liner layer, in accordance with someembodiments. The insulating layer 150 is in direct contact with theisolation structure 120 and the semiconductor substrate 110, inaccordance with some embodiments. The insulating layer 150 is in directcontact with the liner layer 122, in accordance with some embodiments.

In some embodiments, the insulating layer 150 is used to electricallyisolate the light-sensing regions 118 from one another to reduceelectrical crosstalk between the light-sensing regions 118. Theinsulating layer 150 includes silicon dioxide, in accordance with someembodiments. The insulating layer 150 includes a high-k material, adielectric material, or other suitable insulating materials. The high-kmaterial may include hafnium oxide, tantalum pentoxide, zirconiumdioxide, aluminum oxide, other suitable materials, or a combinationthereof.

The dielectric material includes, for example, silicon nitride, siliconoxynitride, other suitable materials, or a combination thereof. Theinsulating layer 150 is formed by, for example, a thermal oxidationprocess or a deposition process, such as a chemical vapor depositionprocess or a physical vapor deposition process.

Thereafter, as shown in FIG. 1C, a light-blocking structure 160 isformed in the trench 119, in accordance with some embodiments. Thelight-blocking structure 160 is formed over the insulating layer 150, inaccordance with some embodiments. A top surface 150 a of the insulatinglayer 150 and a top surface 160 a of the light-blocking structure 160are substantially coplanar, in accordance with some embodiments.

The light-blocking structure 160 and the insulating layer 150 togetherform an isolation structure S, in accordance with some embodiments. Insome embodiments, the isolation structure S is used to separate thelight-sensing regions 118 from one another, and to electrically isolateneighboring devices (e.g. transistors) from one another.

The isolation structure S extends from the back surface 114 into thesemiconductor substrate 110, in accordance with some embodiments. Theisolation structure S surrounds each of the light-sensing regions 118,in accordance with some embodiments. The isolation structure S issubstantially aligned with the isolation structure 120, in accordancewith some embodiments.

The isolation structure S is in direct contact with the isolationstructure 120, in accordance with some embodiments. The isolationstructures 120 and S may reduce optical crosstalk and electricalcrosstalk between adjacent light-sensing regions 118.

FIG. 1C-1 is a top view of an intermediate structure of the image sensordevice of FIG. 1C, in accordance with some embodiments. FIG. 1C is across-sectional view illustrating the intermediate structure of theimage sensor device along a sectional line I-I′ in FIG. 1C-1, inaccordance with some embodiments. As shown in FIGS. 1C and 1C-1, thetrench 119 and the isolation structure S therein surround each of thelight-sensing regions 118, in accordance with some embodiments.

The insulating layer 150 is between the light-blocking structure 160 andthe semiconductor substrate 110 to separate the light-blocking structure160 from the semiconductor substrate 110, in accordance with someembodiments. The insulating layer 150 electrically insulates thelight-blocking structure 160 from the semiconductor substrate 110, inaccordance with some embodiments.

The trench 119 is filled with the insulating layer 150 and thelight-blocking structure 160, in accordance with some embodiments. Thelight-blocking structure 160 is between each two adjacent light-sensingregions 118, in accordance with some embodiments. The light-blockingstructure 160 is used to block incident light to prevent the incidentlight from traveling between different light-sensing regions 118, inaccordance with some embodiments.

In some embodiments, the light-blocking structure 160 includes a lightreflection structure. In some embodiments, the light reflectionstructure has a lower refractive index than that of the semiconductorsubstrate 110, and therefore a portion of the incident light arriving atthe light reflection structure is reflected, which is a phenomenoncalled “total internal reflection”. The light reflection structureincludes dielectric materials, such as silicon dioxides, siliconnitrides, or silicon carbides.

In some embodiments, the light reflection structure has a lightreflectivity ranging from about 60% to about 100%. In some embodiments,the light reflection structure includes a metal material or an alloymaterial. The light reflection structure includes Al, W, Cu, Ti, analloy thereof, a combination thereof, or another suitable reflectivematerial.

Alternatively, in some embodiments, the light-blocking structure 160includes a light absorption structure. In some embodiments, the lightabsorption structure has a light absorptivity ranging from about 60% toabout 100%. In some embodiments, the light absorption structure is usedto absorb the incident light arriving at the light absorption structureto prevent the incident light from traveling between differentlight-sensing regions 118.

In some embodiments, the light absorption structure includes a blacksilicon material, a semiconductor material with a band gap smaller than1.5 eV (e.g., Ge, InSb, or InAs), or a polymer material (e.g., an opaquepolymer material). In some embodiments, the light absorption structureincludes a non-visible light filter (e.g. an IR filter or a UV filter)enabled to block visible light and transmit non-visible light.

In some embodiments, the method of forming the light-blocking structure160 includes depositing a light-blocking material layer on thesemiconductor substrate 110 and filled in the trench 119; and removingthe light-blocking material layer outside of the trench 119.

The method of depositing the light-blocking material layer includesperforming a chemical vapor deposition (CVD) process, a physical vapordeposition (PVD) process, a coating process, or another suitableprocess. The method of removing the light-blocking material layeroutside of the trench 119 includes performing a chemical mechanicalpolishing (CMP) process or another suitable process.

Thereafter, as shown in FIG. 1D, an anti-reflection coating (ARC) layer170 and a buffer layer 180 are sequentially formed over the back surface114 of the semiconductor substrate 110, in accordance with someembodiments. The ARC layer 170 is used to reduce optical reflection fromthe back surface 114 of the semiconductor substrate 110 to ensure thatmost of an incident light enters the light-sensing regions 118 and issensed.

The ARC layer 170 may be made of a high-k material, a dielectricmaterial, other applicable materials, or a combination thereof. Thehigh-k material may include hafnium oxide, tantalum pentoxide, zirconiumdioxide, aluminum oxide, other suitable materials, or a combinationthereof. The dielectric material includes, for example, silicon nitride,silicon oxynitride, other suitable materials, or a combination thereof.

The buffer layer 180 is used as a buffer between the ARC layer 170 andsubsequently formed overlying layers. The buffer layer 180 may be madeof a dielectric material or other suitable materials. For example, thebuffer layer 180 is made of silicon dioxide, silicon nitride, siliconoxynitride, other applicable materials, or a combination thereof.

Thereafter, as shown in FIG. 1D, a grid layer 190 is formed over thebuffer layer 180, in accordance with some embodiments. The grid layer190 is over the isolation structures S and 120, in accordance with someembodiments. The grid layer 190 and the isolation structures S and 120are aligned with each other, in accordance with some embodiments. Theisolation structure S is between the grid layer 190 and the isolationstructure 120, in accordance with some embodiments.

The grid layer 190 has openings 192, in accordance with someembodiments. The openings 192 expose portions of the buffer layer 180,in accordance with some embodiments. The openings 192 are respectivelyand directly over the light-sensing regions 118, in accordance with someembodiments. The grid layer 190 is used to prevent the incident lightfrom entering a neighboring light-sensing region 118, in accordance withsome embodiments. The crosstalk problems between the light-sensingregions 118 are thus prevented or reduced.

In some embodiments, the grid layer 190 is made of a reflective materialsuch as a metal material. The grid layer 190 may be made of aluminum,silver, copper, titanium, platinum, tungsten, tantalum, tantalumnitride, other suitable materials, or a combination thereof. In someembodiments, the grid layer 190 is made of an oxide material such assilicon oxide. In some embodiments, the grid layer 190 is formed overthe buffer layer 180 using a suitable process. The suitable processincludes, for example, a PVD process, an electroplating process, a CVDprocess, other applicable processes, or a combination thereof.

Afterwards, as shown in FIG. 1D, a transparent layer 210 is formed overthe grid layer 190 and the buffer layer 180, in accordance with someembodiments. The transparent layer 210 is filled into the openings 192,in accordance with some embodiments. The transparent layer 210 is madeof oxides (e.g., silicon dioxide), nitrides (e.g., silicon nitride),oxide nitrides (e.g., silicon oxynitride), a polymer material, oranother suitable transparent material through which light (e.g., visiblelight or invisible light) can pass, in accordance with some embodiments.

In some embodiments, the transparent layer 210 and the grid layer 190are made of different materials, in accordance with some embodiments.The transparent layer 210 is formed using a chemical vapor depositionprocess, a physical vapor deposition process, another suitabledeposition process, a spin coating process, or another suitable process.

Thereafter, as shown in FIG. 1E, portions of the transparent layer 210are removed to form recesses 212 in the transparent layer 210, inaccordance with some embodiments. The recesses 212 are right over theopenings 192, in accordance with some embodiments. The recesses 212extend into the openings 192, in accordance with some embodiments.

After the removal process of the portions of the transparent layer 210,the transparent layer 210 remaining over the grid layer 190 forms aspacer structure 214, in accordance with some embodiments. The spacerstructure 214 continuously surrounds the recesses 212, in accordancewith some embodiments.

After the removal process of the portions of the transparent layer 210,the transparent layer 210 remaining in the openings 192 forms baselayers 216, in accordance with some embodiments. The base layers 216 arerespectively in the openings 192, in accordance with some embodiments.

The base layers 216 are respectively under the recesses 212, inaccordance with some embodiments. The base layers 216 are separated fromeach other by the grid layer 190 therebetween, in accordance with someembodiments. The portions of the transparent layer 210 are removed usingan etching process, such as a dry etching process, in accordance withsome embodiments.

FIG. 1F-1 is a top view of an intermediate structure of the image sensordevice of FIG. 1F, in accordance with some embodiments. FIG. 1F is across-sectional view illustrating the intermediate structure of theimage sensor device along a sectional line I-I′ in FIG. 1F-1, inaccordance with some embodiments.

Afterwards, as shown in FIG. 1F and 1F-1, portions of the base layers216 are removed to form a trench 216 a in each of the base layers 216,in accordance with some embodiments. The trench 216 a surrounds portions216 b of the corresponding base layer 216, in accordance with someembodiments. As shown in FIG. 1F-1, the portions 216 b have a roundshape, in accordance with some embodiments. The trench 216 a is directlyconnected with the recess 212 thereover, in accordance with someembodiments. The portions of the base layers 216 are removed using anetching process, such as a dry etching process, in accordance with someembodiments.

FIG. 1G-1 is a top view of an intermediate structure of the image sensordevice of FIG. 1G, in accordance with some embodiments. FIG. 1G is across-sectional view illustrating the intermediate structure of theimage sensor device along a sectional line I-I′ in FIG. 1G-1, inaccordance with some embodiments.

Thereafter, as shown in FIGS. 1G and 1G-1, the portions 216 b arerounded to form lenses E, in accordance with some embodiments. Thelenses E are under the recesses 212, in accordance with someembodiments. The lenses E are entirely or partially in the openings 192,in accordance with some embodiments. The lenses E are formed from theportions 216 b, in accordance with some embodiments. The lenses E andthe spacer structure 214 are made of the same material, in accordancewith some embodiments. Each trench 216 a continuously surrounds thecorresponding lenses E, in accordance with some embodiments.

In some embodiments, the portions 216 b are rounded by performing areflow process over the portions 216 b of the base layers 216. Theprocess temperature of the reflow process ranges from about 50° C. toabout 600° C., in accordance with some embodiments. In some embodiments,the process temperature of the reflow process ranges from about 100° C.to about 600° C. In some other embodiments, the portions 216 b arerounded by performing a wet etching process over the portions 216 b ofthe base layers 216.

The lenses E may include a grid lens array, in accordance with someembodiments. As shown in FIG. 1G-1, the lenses E are arranged in asquare arrangement, in accordance with some embodiments. In some otherembodiments, the lenses E are arranged in a hexagonal arrangement (asshown in FIG. 2).

As shown in FIG. 1G-1, the lenses E have a round shape, in accordancewith some embodiments. In some other embodiments, the lenses E have ahexagonal shape (as shown in FIG. 3). In another embodiment, the lensesE have a tetragonal shape, such as a square shape (as shown in FIGS. 4Aand 4B). FIG. 4B is a perspective view of the lenses E of FIG. 4A, inaccordance with some embodiments.

FIG. 1H-1 is a top view of an intermediate structure of the image sensordevice of FIG. 1H, in accordance with some embodiments. FIG. 1H is across-sectional view illustrating the intermediate structure of theimage sensor device along a sectional line I-I′ in FIG. 1H-1, inaccordance with some embodiments.

Afterwards, as shown in FIGS. 1H and 1H-1, a color filter layer 220 isformed in the recesses 212 and the trenches 216 a, in accordance withsome embodiments. The color filter layer 220 covers the lenses E, inaccordance with some embodiments. The color filter layer 220 is indirect contact with the lenses E, in accordance with some embodiments.The color filter layer 220 in the trenches 216 a surrounds the lenses E,in accordance with some embodiments.

In some embodiments, the color filter layer 220 includes visible lightfilters, such as color filters 220R, 220G, and 220B. In someembodiments, the visible light filters may be used to filter throughvisible light. The color filters 220R, 220G, and 220B may be used tofilter through a red wavelength band, a green wavelength band, and ablue wavelength band, respectively. In some embodiments, thelight-blocking structure 160 includes an invisible light filter (e.g. anIR filter or a UV filter) enabled to block the visible light passingthough the visible light filters.

The spacer structure 214 surrounds the color filters 220R, 220G, and220B, in accordance with some embodiments. In some embodiments (notshown), the spacer structure 214 is not formed.

Afterwards, as shown in FIGS. 1H and 1H-1, lenses 230 are respectivelyformed over the color filters 220R, 220G, and 220B, in accordance withsome embodiments. The lenses 230 are over the lenses E and the gridlayer 190, in accordance with some embodiments. In some embodiments, amaximum thickness T1 of the lens E is less than a maximum thickness T2of the lens 230.

In some embodiments, a maximum width W1 of the lens E is less than amaximum width W2 of the lens 230. In some embodiments, the lenses E havethe same maximum width W1. In some other embodiments, the lenses E havedifferent maximum widths. In some embodiments, the lenses 230 have thesame maximum width W2. In some other embodiments, the lenses 230 havedifferent maximum widths.

In some embodiments, a sum of the maximum widths W1 of the lenses E inthe same opening 192 (or under the same recess 212) and arranged in thesame line is less than the maximum width W2 of the lens 230. The colorfilter layer 220 is between the lenses E and 230, in accordance withsome embodiments. The color filter layer 220 is in direct contact withthe lenses 230, in accordance with some embodiments.

The lenses 230 are used to direct or focus the incident light, inaccordance with some embodiments. The lenses 230 may include a microlensarray. The lenses 230 may be made of a high transmittance material. Forexample, the high transmittance material includes transparent polymermaterial (such as polymethylmethacrylate, PMMA), transparent ceramicmaterial (such as glass), other applicable materials, or a combinationthereof. In this step, an image sensor device 100 is substantiallyformed, in accordance with some embodiments.

In some embodiments, the lenses 230 and E are made of the same material.In some other embodiments, the lenses 230 and E are made of differentmaterials. In some embodiments, the refractive index of the material ofthe lenses 230 is less than the refractive index of the material of thelenses E.

As shown in FIG. 1H, an incident light L sequentially passes through thelens 230, the color filters 220R, and the lens E, in accordance withsome embodiments. Since the lens E directs (or focuses) the incidentlight L, the incident light L arrives at the light-blocking structure160 (instead of passes through the gap between the grid layer 190 andthe light-blocking structure 160) and is absorbed or reflected by thelight-blocking structure 160, in accordance with some embodiments.Therefore, the lens E may reduce optical crosstalk between adjacentlight-sensing regions 118, in accordance with some embodiments. As aresult, the lens E improves the light collection efficiency of the imagesensor device 100, in accordance with some embodiments.

In the image sensor device 100, the isolation structure 120 extends fromthe front surface 112 into the semiconductor substrate 110, inaccordance with some embodiments. The isolation structure 120 surroundsthe light-sensing regions 118, in accordance with some embodiments.

FIGS. 5A-5B are cross-sectional views of various stages of a process forforming an image sensor device 500, in accordance with some embodiments.As shown in FIG. 5A, the steps of FIGS. 1A-1E are performed, inaccordance with some embodiments. The recesses 212 of the transparentlayer 210 are right over the openings 192 of the grid layer 190, inaccordance with some embodiments. The recesses 212 do not extend intothe openings 192, in accordance with some embodiments.

As shown in FIG. 5B, the steps of FIGS. 1F-1H are performed, inaccordance with some embodiments. The lenses E are positioned outside ofthe openings 192, in accordance with some embodiments. The lenses E arepositioned in the recesses 212, in accordance with some embodiments. Inthis step, an image sensor device 500 is substantially formed, inaccordance with some embodiments.

FIG. 6 is a cross-sectional view of an image sensor device 600, inaccordance with some embodiments. As shown in FIG. 6, the image sensordevice 600 is similar to the image sensor device 100 of FIG. 1H, exceptthat the trenches 216 a pass through the base layers 216, in accordancewith some embodiments.

FIG. 7 is a cross-sectional view of an image sensor device 700, inaccordance with some embodiments. As shown in FIG. 7, the image sensordevice 700 is similar to the image sensor device 100 of FIG. 1H, exceptthat the lenses E of the image sensor device 700 have different widthsand different maximum thicknesses, in accordance with some embodiments.

For example, the lenses E include lenses E1, E2, and E3, in accordancewith some embodiments. In some embodiments, a width W3 of the lens E1 isgreater than a width W4 of the lens E2. In some embodiments, the widthW4 is greater than a width W5 of the lens E3. In some embodiments, amaximum thickness T3 of the lens E1 is greater than a maximum thicknessT4 of the lens E2. In some embodiments, the maximum thickness T4 isgreater than a maximum thickness T5 of the lens E3.

FIG. 8 is a cross-sectional view of an image sensor device 800, inaccordance with some embodiments. As shown in FIG. 8, the image sensordevice 800 is similar to the image sensor device 100 of FIG. 1H, exceptthat there is only one lens E in each opening 192, in accordance withsome embodiments. The image sensor devices 100, 500, 600, 700, and 800of FIGS. 1H, 5B, and 6-8 are back side image (BSI) sensor devices, inaccordance with some embodiments. In one embodiments, the lenses E inthe openings 192 have the same maximum thickness T6.

FIG. 9 is a cross-sectional view of an image sensor device 900, inaccordance with some embodiments. As shown in FIG. 9, the image sensordevice 900 is similar to the image sensor device 800 of FIG. 8, exceptthat the lenses E include lenses E4, E5, E6 having different maximumthicknesses T7, T8, and T9, in accordance with some embodiments. In someembodiments, the maximum thickness T7 of the lens E4 is greater than themaximum thickness T8 of the lens E5. In some embodiments, the maximumthickness T8 is greater than the maximum thickness T9 of the lens E6.

FIG. 10 is a cross-sectional view of an image sensor device 1000, inaccordance with some embodiments. As shown in FIG. 10, the image sensordevice 1000 is similar to the image sensor device 100 of FIG. 1H, exceptthat the image sensor device 1000 is a front side image sensor device,in accordance with some embodiments.

That is, in the image sensor device 1000, the ARC layer 170, the bufferlayer 180, the grid layer 190, the base layers 216 (having the lensesE), the spacer structure 214, the color filter layer 220, and the lenses230 are formed over the interconnection structure 130 (or the frontsurface 112 of the semiconductor substrate 110), in accordance with someembodiments. In some embodiments, the image sensor device 1000 does notinclude the isolation structure S. In some other embodiments (notshown), the image sensor device 1000 includes the isolation structure S.

In accordance with some embodiments, image sensor devices and methodsfor forming the same are provided. The methods (for forming the imagesensor device) form a first lens and a second lens over the first lens,and the first lens is able to direct (or focus) an incident lightpassing through the second lens to a light-sensing region under thefirst lens. Therefore, the first lens reduces optical crosstalk betweenadjacent light-sensing regions. The first lens improves the lightcollection efficiency of the image sensor device.

In accordance with some embodiments, an image sensor device is provided.The image sensor device includes a substrate. The image sensor deviceincludes a light-sensing region in the substrate. The image sensordevice includes an isolation structure in the substrate. The isolationstructure surrounds the light-sensing region. The image sensor deviceincludes a grid layer over the substrate. The grid layer is over theisolation structure. The image sensor device includes a first lens overthe light-sensing region and surrounded by the grid layer. The imagesensor device includes a color filter layer over and in direct contactwith the first lens. The first lens is embedded in the color filterlayer. The image sensor device includes a second lens over the colorfilter layer.

In accordance with some embodiments, an image sensor device is provided.The image sensor device includes a substrate. The image sensor deviceincludes a light-sensing region in the substrate. The image sensordevice includes an isolation structure in the substrate. The isolationstructure surrounds the light-sensing region. The image sensor deviceincludes a grid layer over the substrate. The grid layer is over theisolation structure. The image sensor device includes a first lens and asecond lens over the light-sensing region and surrounded by the gridlayer. The first lens is adjacent to and connected with the second lens.The image sensor device includes a third lens over the first lens, thesecond lens, and the grid layer. The image sensor device includes acolor filter layer between the first lens and the third lens and betweenthe second lens and the third lens, wherein a lower portion of the colorfilter layer separates a first top portion of the first lens from asecond top portion of the second lens.

In accordance with some embodiments, an image sensor device is provided.The image sensor device includes a substrate. The image sensor deviceincludes a light-sensing region in the substrate. The image sensordevice includes an isolation structure in the substrate. The isolationstructure surrounds the light-sensing region. The image sensor deviceincludes a grid layer over the substrate. The grid layer is over theisolation structure. The image sensor device includes a first lens overthe light-sensing region and surrounded by the grid layer. The imagesensor device includes a spacer structure over the grid layer. Thespacer structure surrounds the first lens. The image sensor deviceincludes a second lens over the first lens and the spacer structure. Theimage sensor device includes a color filter layer between the first lensand the second lens. The color filter layer has a curved bottom surface.

The foregoing outlines features of several embodiments so that thoseskilled in the art may better understand the aspects of the presentdisclosure. Those skilled in the art should appreciate that they mayreadily use the present disclosure as a basis for designing or modifyingother processes and structures for carrying out the same purposes and/orachieving the same advantages of the embodiments introduced herein.Those skilled in the art should also realize that such equivalentconstructions do not depart from the spirit and scope of the presentdisclosure, and that they may make various changes, substitutions, andalterations herein without departing from the spirit and scope of thepresent disclosure.

What is claimed is:
 1. An image sensor device, comprising: a substrate;a light-sensing region in the substrate; an isolation structure in thesubstrate, wherein the isolation structure surrounds the light-sensingregion; a grid layer over the substrate, wherein the grid layer is overthe isolation structure; a first lens over the light-sensing region andsurrounded by the grid layer; a color filter layer over and in directcontact with the first lens, wherein the first lens is embedded in thecolor filter layer; and a second lens over the color filter layer. 2.The image sensor device as claimed in claim 1, wherein a lower portionof the color filter layer is embedded in the grid layer.
 3. The imagesensor device as claimed in claim 2, wherein the lower portion of thecolor filter layer surrounds the first lens.
 4. The image sensor deviceas claimed in claim 1, the second lens is in direct contact with thecolor filter layer.
 5. The image sensor device as claimed in claim 1,further comprising: a spacer structure between the grid layer and thesecond lens, wherein the spacer structure surrounds the first lens. 6.The image sensor device as claimed in claim 5, wherein the spacerstructure and the first lens are made of a same material.
 7. The imagesensor device as claimed in claim 6, wherein the color filter layer isin direct contact with the spacer structure.
 8. The image sensor deviceas claimed in claim 6, wherein the spacer structure surrounds the colorfilter layer.
 9. The image sensor device as claimed in claim 1, whereinthe grid layer surrounds the color filter layer.
 10. The image sensordevice as claimed in claim 1, wherein a first top surface of the firstlens is lower than a second top surface of the grid layer.
 11. An imagesensor device, comprising: a substrate; a light-sensing region in thesubstrate; an isolation structure in the substrate, wherein theisolation structure surrounds the light-sensing region; a grid layerover the substrate, wherein the grid layer is over the isolationstructure; a first lens and a second lens over the light-sensing regionand surrounded by the grid layer, wherein the first lens is adjacent toand connected with the second lens; a third lens over the first lens,the second lens, and the grid layer; and a color filter layer betweenthe first lens and the third lens and between the second lens and thethird lens, wherein a lower portion of the color filter layer separatesa first top portion of the first lens from a second top portion of thesecond lens.
 12. The image sensor device as claimed in claim 11, whereina width of the lower portion of the color filter layer increases towardthe third lens.
 13. The image sensor device as claimed in claim 11,wherein the first lens is interposed between the grid layer and thesecond lens, and a first width of the first lens is greater than asecond width of the second lens
 14. The image sensor device as claimedin claim 13, wherein a first thickness of the first lens is differentfrom a second thickness of the second lens.
 15. The image sensor deviceas claimed in claim 14, wherein the first thickness is greater than thesecond thickness.
 16. An image sensor device, comprising: a substrate; alight-sensing region in the substrate; an isolation structure in thesubstrate, wherein the isolation structure surrounds the light-sensingregion; a grid layer over the substrate, wherein the grid layer is overthe isolation structure; a first lens over the light-sensing region andsurrounded by the grid layer; a spacer structure over the grid layer,wherein the spacer structure surrounds the first lens; a second lensover the first lens and the spacer structure; and a color filter layerbetween the first lens and the second lens, wherein the color filterlayer has a curved bottom surface.
 17. The image sensor device asclaimed in claim 16, wherein the curved bottom surface is a concavecurved surface.
 18. The image sensor device as claimed in claim 16,wherein an upper portion of the color filter layer passes through thespacer structure, and a lower portion of the color filter layer isembedded in the grid layer.
 19. The image sensor device as claimed inclaim 16, wherein the color filter layer is in direct contact with thefirst lens, the second lens and the spacer structure.
 20. The imagesensor device as claimed in claim 16, wherein the spacer structure andthe first lens are made of a same material, and a first top surface ofthe spacer structure is substantially level with a second top surface ofthe color filter layer.